(1) Field of the Invention
This invention is directed to cassettes used with devices such as typewriters or text printers which utilize at least two different cassettes, such as a ribbon cassette and a correcting cassette.
(2) Description of the Prior Art
Various prior art devices disclose means by which the operability of a typewriter or printer is controlled by the condition or type of cassette present in the typewriter or printer. U.S. Pat. No. 4,636,097, for example, includes means for rendering the printer inoperable when the end of the typewriter ribbon in a cassette is sensed, or when there is no cassette in the printer. Another such device is disclosed in IBM Technical Disclosure Bulletin, "Low Cost Cartridge Code Detector," Craft, Volume 25, No. 4, September 1982, pp. 1980, 1981. The cassette disclosed therein provides a signal to the device (such as a typewriter) which identifies the contents of the cassette, so that the device may adjust to the characteristics of the cassette contents. Still another such device is disclosed in U.S. Pat. No. 4,516,137 wherein the presence or absence of a thermal ribbon cassette is sensed by the printer. If a thermal ribbon cassette is present, the printer can print only unidirectionally, whereas when the ribbon cassette is not present, the printer prints bi-directionally.
There are, in addition, prior art devices which disclose means for connecting a ribbon cassette to a correcting cassette. Examples of such prior art devices are U.S. Pat. No. 4,239,107 and U.S. Pat. No. 4,302,118. The '118 patent discloses mating formations adapted to place a ribbon cassette in register with a correcting cassette, and also discloses means on the cassette which control the selection of the correct feed and ribbon lift mechanism.